Manufacture of large crystals.



JOHANNES BOOK, OF RADEBEUL, NEAR DRESDEN, GERMANY.

IANUI'ACTUBE LARGE CRYSTALS.

Specification of Letters Patent.

Patented Jan. 26, 1909.

Application fled larch 12, 1907. Serial No. 381,966. (Specimens) To onwhom it may concern:

Be it lmown that I, JOHANNES BooK, chemist, a subject of the GermanEmperor, residing at Radebeul, near Dresden, Saxony,

Germany, have invented certain new and useful Improvements in orRelating-to Improved Manufacture of Large Crystals; anddo hereby.declarethe following to be a full,

clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

In the manufacture of large 0 stals the proceeding is often such that sm"crystals or powder of crystals are thrown into the solut1on to becrystallized and allowed to grow. As a rule the growth of such crystalstakes place very slowly, so that weeks and months are necessary, inorder to obtain large crystals, as the crystallization of the dissolvedsubstance must take place slowly, in order to prevent the formation ofnew crystals.

Now I have found that by introducing c stal s linters into the'solutlonto be crys- 25 t 'zed arge crystals can be produced in a very muchshorter time than by introducing complete crystals or powder of crystalsinto the solution. Splinters of crystals show a tendency to regeneratethe original shape of 80 the crystal from which they have been roduced,and thus regain very quickl t eir full original size. Acrystal splintero 1 c. m. length of edge grows for instance to a complete crystal ofsuch size that its lateral surface is one o. m. long and its otherdimensions are of corresponding size. The ener of growth of such crystalsplinters in a sufii clently concentrated solution is at. least twice orthree times that of complete crystal individuals.

According I to the present process large crystal linters are introducedinto the solution to e crystallized in order to obtain large crytals.

To perform my invention in practice, I proceed as follows: I break upcom lete cryiaitals and '1 separate the obtained arge sp ters from thesmall splinters and the powder by sieving or in another manner, in

order to obtain splinters of the desired size. The larger splinters maybe if a determined size of cryst is to be produced.

If this is not desired, the broken the crystal splinters and especi thesubstance to be crystallized and the solution is crystallized in theusual manner by cooling or by concentrating the solution. Thecrystallizing substance dgplosits upon y on those parts from which theedges and surfaces of the original crystal have been removed. As thecrystal splinters can attract a much larger quantity of substance, thancomplete crystals the cooling or the evaporation can ta e place muchmore quickly than in the usual process, in which complete crystals areemployed. For this reason the crystallization of hot saturated solutionsalso takes place more quicklyby the introduction of crystal splintersinto the solution than by the em loyment of complete crystals. Thecrystall ization with crystal sphnters therefore represents aconsiderable advantage in certain cases.

As the substance 0 stallizing from the original solution genera ly isnot sufiicient to form large and com lete crystals from the introducedcrystal sp ters, the c stallized solution is replaced by a fresh soution, or new mother solution is added to the solution as usually in thecrystallization by evaporation of the solvent. This latter process iscarried on until the employed crystal sphnters have been transformedinto full and corn lete crystals.

aving now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is:

Process of producing large crystals from hot concentrated solutions,which consists in breaking up large crystals selparating the small slinters produced from t e large splinters ans putting the largesplinters in concentrated solutions of the matter to be crystallized,and causing the crystallization of said solution.

my hand presence of two witnesses.

WoLnnuAa Ham, Harm! Hssrna.

